61.局域网中某主机的IP地址为202.,116.1.12/21,该局域网的子网掩码为( )
A.255.255.255.0
B.255,255.252.0
C.255.255.248.0
D.255.255.240.0
62.如果访问一个网站速度很慢,可能有多种原因,但首先应该排除的是( )
A.网络服务器忙
B.通信线路忙
C.本地终端感染病毒
D.没有访问权限
63.The term“software ( )” is used to describe the software engineering activities that occur following delivery of a software product to the customer
A. analysis
B. maintenance
C. design
D. implementation
64.( ) testing ensures that a software module operates correctly and reliably.
A. Application B. Integration C. System D. Unit
65.( )refers to the range of computer hardware and OS platforms on which the source code of a program can be compiled and run.
A. Usability B. Portability C. Reliability D. Maintainability
66.A computer ( )is a program that maliciously causes unwanted behavior on a computer
A. software B. application C. virus D. process
67.( )makes computers able to do jobs which till now, only human brains can do.
A. Artificial intelligence
B. Big data
C. Cloud computing
D. Internet of things